


Birthday Bonding

by lesbianpapyrus



Category: Undertale (Video Game)
Genre: Birthday Party, Gen, Rated T for language, other characters appear
Language: English
Status: Completed
Published: 2019-04-09
Updated: 2019-04-09
Packaged: 2020-01-07 13:26:59
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,308
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18411578
Author URL: https://archiveofourown.org/users/lesbianpapyrus/pseuds/lesbianpapyrus
Summary: It's Asgore's birthday, and Undyne and Mettaton have seemingly conflicting ideas for a party.





	Birthday Bonding

How marvelous it was, to be on the surface! Asgore had truly thought that he would never make it up here peacefully, yet here he was, living with a wonderful family in a wonderful world where humans and monsters loved and accepted one another.

One year ago, Asgore never would have expected that he would be celebrating his next birthday in the sunshine. So much had happened in such a short amount of time, and he wondered if his mind would ever truly come to terms with all of it.

But he knew one thing for sure. He had had so many lonely birthdays in the past that this year he only wanted to spend it with his family. He didn’t expect much, except perhaps a little tea party with a simple cake and maybe a few presents.

Of course, his family had other plans.

Undyne was more excited for Asgore’s birthday than he was. He had been her father-figure since her birth father had passed away, after all, and she was going to make sure he would never forget his first birthday on the surface. She stayed up late a week before the special day, planning all the details for a surprise party. Fun and games would be the theme, she decided—lots of physical activity. Of course, some time would be set aside for cake and presents, but then it’d be back to roughhousing!

However, Undyne was not the only person to decide that Asgore’s birthday was an extra special occasion.

Mettaton had also taken it upon himself to plan a surprise party for Asgore, and his ideas couldn’t have been more different from Undyne’s. Roughhousing never once entered his mind—instead, he dreamed up visions of a party with tea and dancing and only the fanciest and richest of foods. He’d have to hire a caterer for the event and buy glittery decorations and put together a playlist of his best songs to dance to—what fun!

He couldn’t wait to tell his boyfriend about this.

“Oh, Papyruuuuus!” he practically sang into his phone the evening he made all his plans. “Papy, I had the most wonderful idea for Asgore’s birthday this year. We should throw him a surprise party! I have so many plans for it—”

“Oh, that’s great, Mettaton!” Papyrus agreed enthusiastically. “You and Undyne can work together!”

“Me and—and Undyne? What’s she got to do with this?” Mettaton demanded.

“Well, she texted me earlier today saying she’d had an idea for a surprise party for Asgore last night. You two really should work together! I bet you’ll come up with something almost as great as something the Great Papyrus would!”

After he had hung up from the phone call, Mettaton groaned. He couldn’t believe he would have to collaborate with _Undyne_ of all people in order to pull off a party. Why couldn’t it have been Alphys? Or Toriel? Or anyone but that obnoxious fish? There was no way the two of them wouldn’t fight every minute putting it all together.

Mettaton thought fast. He could refuse to work with her… but then the party would probably end up a disaster in his eyes. No, he couldn’t back down. He’d have to find some way to convince Undyne that his plan was better. One way or another, he certainly wouldn’t be using _her_ ideas.

Undyne was of a similar mindset when Papyrus texted her a few minutes later.

6:42 P.M.          UNDYNE! I HAVE SOME GREAT NEWS!

6:46 P.M.          Yeah, dude? What’s up?

6:51 P.M.          METTATON WANTS TO HOLD A SURPRISE PARTY FOR ASGORE, TOO! YOU TWO ARE GOING TO HAVE TO WORK TOGETHER! WON’T THAT BE FUN?!

6:56 P.M.          What.

7:01 P.M.          I WILL REPEAT MYSELF. METTATON WANTS TO HOLD A SURPRISE PARTY FOR ASGORE, TOO! YOU TWO ARE GOING TO HAVE TO WORK TOGETHER! WON’T THAT BE FUN?!

Undyne did not reply right away, too busy trying to overcome her horror.

That stupid, obnoxious robot… why did he always have to ruin everything?

7:10 P.M.          HELLO??

7:12 P.M.          Sorry dude. Yeah. Uh. Fun. Thanks for telling me.

Angrily, Undyne threw her phone across the room. She would outright refuse to work with him, except the party was likely to be a disaster in that case, at least in her eyes.

No, she wasn’t going to back down, and she doubted Mettaton would, either.

They’d have to work together to set everything up. But at least until then, Undyne could focus on her own plan and getting everything she needed for that.

Ω

The day of the party came much faster than either Undyne or Mettaton wanted, and they had still not spoken to each other about any of their plans. They both arrived at Toriel’s house, where the party would be held, at noon, eyeing each other unpleasantly as they got out of their cars.

“Alright, listen up, ro-butt,” Undyne growled at Mettaton when they both reached the front door at the same time. “Asgore was my dad first, so I have seniority. _I’m_ going to call the shots around here.”

“Is that what you really think?” Mettaton drawled, knocking on the door. “Fat chance, darling. I won’t be intimidated out of my plans this time.”

Both of them put on big smiles for Toriel when she answered the door. “Thank heavens,” she sighed, slinging a big purse over her shoulder. “Frisk and Flowey and I are going to do some last-minute gift shopping. You two can set everything up while we’re gone. Do try not to set the house on fire,” she added to Undyne, which made Mettaton smirk.

After Toriel, Frisk, and Flowey had left, Mettaton and Undyne were left standing in the foyer. Mettaton tossed his hair and said, “Well, let’s get it over with already.”

Undyne only grunted in response. She headed for the backyard first, sizing it up for the sparring ring she wanted to create. Mettaton went back to his car to retrieve a bag of Christmas lights, then walked around the house to the deck and began stringing them up.

Undyne came up on the deck, watching him critically. “What are you _doing?”_

Without looking at her, Mettaton replied, “Creating the perfect atmosphere for a dance floor.”

“Dance floor? We’re not going to be doing any dancing. There _is_ going to be a wrestling match, and a fighting competition!” she shot back, eyes blazing with excitement.

Mettaton’s eyes in turn were bugging out with horror. “Wrestling? Fighting? At _my_ fancy party? Excuse my French, dear heart, but I think the fuck not! Asgore deserves to have _fun_ on his birthday, not muss up all his clothes in some silly competition!”

“It _is_ fun! Not silly! Asgore likes to spar!” retorted Undyne hotly. “He’s better at it than he is at _dancing!”_

“He likes to dance, too! And have tea and cakes and good food, which _I’m_ going to provide for him!”

“I had plans for tea and cake, too! It’s just not as important as having fun. Which is why we should play games and spar!”

The two of them were in each other’s faces at this point.

“Who ever heard of sparring at a party? _Nobody_ spars at a party!” Mettaton scoffed. “Absolutely ludicrous!”

“Nobody likes all your fancy shit, either! It just makes everyone uncomfortable!”

“It only makes _you_ uncomfortable!”

“Well, whatever! Set up whatever the fuck you want, and I’ll set up whatever the fuck _I_ want, and we’ll let Asgore decide whose party is better!” Undyne stormed off the deck back to her project.

“Fine!”

_“Fine!”_

Mettaton kicked a nearby chair angrily, then calmed himself down. At least Undyne wasn’t out to completely sabotage his plans. He just needed to set up his own decorations and get all the food ready, and surely Asgore would choose his own tasteful, fancy party over Undyne’s mess.

Meanwhile, Undyne restrained herself from tearing clumps of grass from the ground. She couldn’t let that idiot robot get to her. She would set up her own party stuff, and Asgore would definitely see that her ideas were more fun than Mettaton’s boring nonsense.

So they each set up their own party. Undyne created a makeshift fighting ring by driving four sticks into the ground in the shape of a square, each stick exactly twenty feet apart from the others. Then she used a can of spray paint to put down lines stretching from one stick to another. She then dragged a big soccer net from the side of the house and set it up beyond her fighting ring in case everyone decided they wanted to kick a ball around. When she was done, she stood back to admire her handiwork.

Across the yard, Mettaton shook his head and got to work. He finished stringing up the Christmas lights and cleared the deck of all furniture to make his dance floor, then set up speakers connected to an iPhone dock for music. Then he went inside and set the dining room table with Toriel’s best china plates and crystal glasses, and decorated the rest of the first floor with glittery pink banners. Lastly, he called his caterer and told them to bring all the food for the party around two-thirty.

When he was finished, he went back out to the back deck and tutted at Undyne. “How much effort did you even put into this? It hardly looks like you’ve done anything,” he jeered.

“Shut up, you overgrown lightning rod!” Undyne spun around and practically charged up to the deck to get in his face. “Maybe it doesn’t look like much, but it’s not about the looks. It’s about all the fun we’ll have with it later! And that’s more than I can say for your boring-ass funeral dinner over there!”

“Funeral—?” Mettaton’s mouth dropped open. “Why don’t _you_ shut up? Just because _you_ have no taste in parties doesn’t mean _everyone_ does!”

Before Undyne could retort, they both heard the front door of the house open. Toriel, Frisk, and Flowey were back, and with them were almost all the other members of the family—Papyrus, Sans, Grillby, Lulu, Alphys, and Napstablook. Papyrus looked admiringly at all the decorations. “Wowie! You guys sure did a great job in here!”

“You mean _I_ did a great job in here. Undyne had nothing to do with this!” Mettaton declared. “She’s been working on the utter drivel in the backyard.”

Papyrus came out onto the deck and looked at Undyne’s handiwork. “Oh, wow! Are we going to have a sparring competition? That’ll be fun!”

“Hell yeah, we’re gonna have a sparring competition!” Undyne threw her arm around Papyrus’s shoulders.

“Only if Asgore chooses your party! And clearly _mine_ is the superior one!” Mettaton grabbed Papyrus’s hand and dragged him away from Undyne.

Papyrus looked between the two, confused. “Chooses your party? What do you mean?”

“Mett-asshole and I weren’t gonna agree on anything, so we just made our own parties and we’re going to let Asgore choose the one he wants.” Undyne glared at Mettaton. “And he’s definitely gonna choose mine because it’s not gonna be some mind-numbing garbage!”

“Oh, very clever nickname, Undies!” Mettaton shot back. “You’re not even thinking about Asgore anymore! You just want to have your party because _you’d_ have fun! And you just want to get one up on me!”

“Oh, please, and you don’t? You don’t want to have your party because _you’d_ have the most fun at it? You don’t wanna get one up on _me?_ You’re the most selfish person I know, so I’d bet my life you’re only thinking about yourself! So fuck you! Maybe _you_ should think about Asgore!”

Horrified by the direction the conversation—if one could even call it that anymore—was taking, Papyrus got between them. “Now, now! I see no reason why—”

“I _have_ been thinking about him this whole time! _You’re_ the selfish one, you just want Asgore all to yourself!” Tears were coursing down Mettaton’s face. “Fuck _you!_ You stupid, _ugly—”_

“That’s ENOUGH!” Toriel thundered through the back door, having heard every word. Her eyes blazed at Undyne and Mettaton. “I have witnessed many arguments in my time, but _never_ have I seen one as petty and unnecessary as this! I have seen _toddlers_ act more maturely than this! I had hoped you two could set aside your differences for someone you both consider a father, but clearly I put too much faith in you. I have never been more ashamed of either of you!”

Completely humiliated, Undyne and Mettaton could only stand there in shock. Everyone else looked at each other silently, unsure what to do.

“Apologize to each other. Now.”

Mettaton made a choking noise and shook his head before turning and running off the deck, around the side of the house.

Anger renewed, Undyne shook her own head and vaulted over the deck railing, then ran to one of the trees in the back of the yard and began punching it.

Disgusted, Toriel sighed and turned to Papyrus. “I hate to ask this of you, dear, but perhaps you could talk some sense into them?”

Papyrus looked unsure for a split second, then he puffed out his chest proudly. “The Great Papyrus will do even better! I’ll have them making up in no time!”

Undyne rather looked as though she might punch anyone who tried to speak to her at this particular moment, so Papyrus looked for Mettaton first. He found him sobbing miserably on the front porch. Papyrus didn’t even get to say anything before Mettaton pulled him down to his level.

“Oh, Papy, I’m so sorry for blubbing like this, but—but I just don’t understand!”

“What don’t you understand?” Papyrus asked gently.

“Why Undyne can’t just listen! Good parties just don’t have silly fighting competitions.”

“And why not?”

The question caught Mettaton off guard. “Well, it’s just—that’s not how it’s done.”

“Why not? Do you have some rule book that says you can’t play games at a party? Or did someone teach you that?”

“Well, no…” Mettaton admitted. “But… that’s not the kind of party _I_ tend to like.”

“But the party isn’t for _you,_ Mettaton,” Papyrus reminded him. “It’s for Asgore.”

“Yes, I know that, but—but the man likes to drink _tea,_ Papyrus, not spar… so I thought a fancy party would be just right for him.”

“Asgore loves to spar! He used to do it with Undyne all the time! In fact, sometimes he joins in when Undyne spars with me!”

“He does?” Mettaton seemed troubled. “I didn’t know that… he only ever seemed to drink tea and talk with me.”

“He trained Undyne for the Royal Guard. Honestly, I think he’d really enjoy her type of party. But!” he added quickly, noting Mettaton’s trembling lower lip, “there is no reason he would not also enjoy your kind of party! In fact, I think he would quite enjoy having both!”

“Both? How could we have both?”

“Imagine it, Mettaton.” Papyrus put an arm around Mettaton’s shoulders. “Imagine we had a sparring competition first, and played all sorts of games. That would work up quite an appetite for all involved, wouldn’t it? So then, we go inside and have your fancy dinner! And then, we relax with some nice music and dancing! Honestly, I think your idea and Undyne’s can mesh together quite well!” He smiled. “Can you see it?”

“Yes, I—I suppose so,” Mettaton said slowly.  Then excitement flared in his chest. “Yes, you’re right! Why didn’t we think of that before? I guess—I guess Undyne and I just disliked each other too much to really put our heads together.” Then his face fell. “But—I’m afraid it’s too late now. Undyne must be too angry at me to make up.”

“We’ll see about that! Just let me talk to her. In fact, let’s both go, so she knows you didn’t send me to do your dirty work!” Papyrus stood and took Mettaton’s hand to help him. “Come on, now!”

Mettaton followed a few paces behind Papyrus as they headed toward Undyne, feeling rather apprehensive.

“Undyne! Mettaton and I would like a word with you!” Papyrus called, entirely too cheerfully considering the situation.

Undyne stopped punching the tree and glowered at Mettaton without saying a word.

Papyrus inclined his head toward Mettaton, prompting him to speak. The robot swallowed and met Undyne’s wrathful gaze shamefacedly. “Undyne… Papyrus talked to me, and—I want to—I feel… well… what I’m trying to say is—I’m sorry. I’m sorry for calling you stupid and ugly, neither of those things are true and it was entirely uncalled for. I know you care a lot about Asgore, and so do I, but—but we don’t need to fight to show who cares the most… we should have been thinking about what he would like. _I_ should have been thinking about what he would like.” He swallowed again and looked away. “I didn’t realize Asgore liked to spar with you. I wouldn’t have ridiculed your idea if I had known… not that I should have ridiculed it anyway. I’m… again, I’m sorry.”

Undyne stared at him a while longer—then, finally, her face softened, and her gaze fell to the ground. “You know… this whole thing was so dumb. Toriel is right, we should have put aside our differences for him, but I don’t think we really wanted to. I know I didn’t.” She kicked a clump of grass. “I should have been thinking about Asgore, too. I knew he wouldn’t really find your party boring… I guess I was just dreading the thought of dressing up or whatever you’d have us all do... and part of me was jealous that all your stuff looked so good, while mine looks…” She gestured to her makeshift fighting ring, grimacing. “But it’s not about me.” She sighed. “I think we both have a lot to apologize for. So… I’m sorry for calling you all those names and stuff. It was beyond childish and stupid. And… as long as it’s Asgore’s birthday, I’m willing to work with you and do whatever you want as long as it makes Asgore happy.”

Mettaton smiled. “Well… it’s not about what I want. I can’t take credit for this—Papyrus had a good idea. He thinks that _both_ our parties can work, that Asgore would really enjoy both. And after he explained it, I think he’s right.” He went on to tell Undyne about Papyrus’s idea. “What do you think about that?”

Undyne clapped a hand on Papyrus’s shoulder. “Pap, dude… you are definitely the genius of this group.”

“There was nothing to it!” Papyrus exclaimed. “Now, are we officially made up here?”

Undyne extended her hand to Mettaton. “Partners?”

Mettaton shook it gratefully. “Partners.”

“Alright, cool. So, uh… is there anything else we need to do before Asgore gets here?” Undyne scratched the back of her neck.

Suddenly Mettaton remembered. “My catering! I’ll certainly need help getting all the food inside and set up. Asgore might be here any minute!”

Undyne wasted no time throwing the robot over her shoulder and carrying him bodily back to the house. “Hey, Pap, if Asgore gets here before we’re done, can you stall him?”

“Of course! The Great Papyrus can do anything you need him to!”

Fortunately, despite the massive amount of food Mettaton had ordered, it didn’t take long to set it all out in the kitchen. Mettaton and Undyne just barely had time to double check decorations before Papyrus alerted them to Asgore coming up the driveway.

Everyone quickly hid in the rooms by the front door and waited impatiently for Asgore to let himself in. As soon as he did, everyone shouted “SURPRISE!” and burst from their hiding spots. Undyne and Mettaton were the first to reach Asgore and give the shocked goat monster warm hugs.

Undyne took his paw and dragged him out to the backyard first, asking if he would care for a sparring competition. Asgore quickly agreed, and Undyne split all the adult monsters who wanted to participate into brackets: Undyne versus Papyrus, Mettaton versus Lulu, Grillby versus Sans, and Toriel versus Asgore.

Undyne and Papyrus went first. It ended up being a long, tough battle, as both monsters were of nearly equal strength and adeptness at magic, but Papyrus eventually allowed Undyne to prevail.

Lulu wasn’t much of a fighter, but she was quite fast at attacking and gave Mettaton a run for the money. After a few minutes, however, she tired out and gave up to the robot.

Sans had clearly only joined the competition to goof off. He and Grillby barely fought; Sans kept falling asleep while his boyfriend threw badly-aimed fire attacks at him. Within five minutes, Sans pretended to fall out of bounds, giving the game to Grillby.

Toriel participated in the competition only to appease Frisk and Flowey, who begged her to play on behalf of them. She tried to make it look as though she were trying to win, but in reality only gave the barest minimum effort to beat her ex-husband. The match finally went to Asgore.

In the next bracket, Undyne pitted herself against Mettaton, thinking she’d enjoy getting to kick the prissy robot’s butt. It was much harder than she thought, however, since Mettaton decided he would also enjoy a chance at defeating Undyne and thus fought with everything he had. Undyne only ended up beating him by throwing so many wild spear attacks that Mettaton backed up over the boundary line.

Grillby and Asgore’s match was barely a match. Though Asgore went easy on the fire monster, who was not used to fighting, Grillby was intimidated enough by the boss monster’s size alone that he pulled a Sans and eventually pretended to cross out of bounds.

So it was down to Undyne and Asgore. This time, neither of them held back, as they were quite used to sparring with each other with everything they had. It took nearly ten minutes for Asgore to finally prevail, and even then, it was only just barely a win for him. Undyne handled her loss quite well, happy that Asgore had won on his birthday.

Mettaton reminded everyone that dinner was waiting for them, and the hungry participants were the first to get into the kitchen and get some of the food. Mettaton seemed to have ordered only the best foods he could find for the adults—lobster, pasta salad, roasted seasoned potatoes, mussels and scallops, and risotto. For the kids, he made sure to get fancy macaroni and cheese and some kind of bean soup that he was sure they would like.

The meal was filled with talk and laughter, and they finished it off with a simple but tasty cake baked by Toriel. Asgore cried as they sang “Happy Birthday” to him and as he opened each gift that the family gave to him when they were finished with the cake.

The sun was setting as everyone went outside to dance. After a few minutes of dancing with Papyrus, Mettaton took a break and leaned against the deck railing, smiling at how happy everyone seemed to be, especially Asgore. Soon he felt a presence beside him.

“Hey. So… I guess we really managed to pull this off, huh?” Undyne said quietly as she gazed at the dancing monsters.

“We did,” Mettaton answered, redirecting his smile to her. “Asgore seems really pleased with it all… that sparring competition was more fun than I thought it would be. Thanks for that.”

“Yeah… well, that dinner was way better than I thought it would be, to be honest. I’m stuffed. I think I’m gonna have you order the food for _my_ birthday.”

“Gladly, darling.”

Their dancing partners reclaimed them, and after another hour, everyone was ready to go home.

On the front porch, Asgore thanked Undyne and Mettaton profusely for their work in putting the party together. “You have no idea how much it means to me that you would work together and do this for me,” he said with tears in his eyes.

Mettaton and Undyne looked at each other. “Well… it really wasn’t easy,” Undyne finally replied. “We definitely needed a kick in the ass to really get going on it. But yeah… we did our best.”

Asgore hugged them both and said his goodbyes. As they watched him leave, Undyne turned to Mettaton and tentatively clapped a hand on his shoulder. “I guess we did good.”

“You did very well,” said Toriel’s voice behind them, and they turned to find her smiling at them. “Thank you for working things out between you.” She went back into the house, leaving them alone together.

To Undyne’s surprise, Mettaton caught her up in a hug. “This was fun… I think we should do it more often.”

Undyne carefully lifted her arms to return the hug, patting his back. “Yeah… I guess we’ve been acting real stupid about each other.” She pulled back and gave a sideways grin. “You’re not bad. Least not as bad as I thought.”

“Gee, thanks,” Mettaton returned sarcastically.

As they went home for the night, the two monsters were a bit surprised at how much of a bonding experience the party had been. Everything had certainly started out roughly, but with the help of Papyrus, they had pulled themselves together and done something wonderful for someone they loved. And in doing so, they had each learned that the other person was different than they had believed.

Now they were closer than before. And each wondered what kinds of experiences lay in store for the two of them that would really make their friendship bloom.

**Author's Note:**

> hey guys! this was requested by a follower of mine on tumblr. hope you enjoy!


End file.
